Installing the correct Air Conditioner unit for your home makes a big impact on your energy bills and comfort. You might think that a bigger AC unit is always better, but that is somehow the opposite. If you purchase a big-size air conditioner unit, it will cool the area quickly. This will cause the AC unit to continuously turn on the compressor and turn it back on, which leads to lower efficiency and higher energy bills (because when the compressor turns back on it consumes more energy) and sometimes more air conditioner maintenance.

On the other hand, if you choose an AC unit that is too small, it will run constantly to cool the area, and in some cases may never deliver the desired temperature or comfort. This increases your energy consumption and may leave cause an uncomfortable environment.

Installing the right sized AC unit in your home is a big responsibility and choosing the wrong size AC unit can affect your energy bills very badly. That is why we recommend leaving the installation process to the professionals and getting a consultation.


Let us look at how AC unit sizes are determined. An air conditioner unit’s cooling capacity is measured in tons based on how many BTUs (British Thermal Units) it can cool in an hour. For example, 1 AC ton unit can cool 12,000 BTUs, a 2-ton AC unit can cool 24,000 BTUs, and like that so on. Residential air conditioners generally start at 1 ton and go up in half-ton increments. Your home or office would rarely need an AC unit larger than 5 tons.

Here are some guidelines to estimate the air conditioner unit size you may need in California. For example, you can roughly calculate that 1 ton is enough to cool per 750-1000 square feet, so a 3,000 square foot home may require a 3.0 – 3.5 ton AC unit. To convert to BTUs per hour, multiply the AC unit size (tons) by 12,000.

Remember that every home is different and factors that will affect the AC unit size, such as the size and number of windows, exposure of those windows to the north and east, and how the home is insulated. The best way to get an exact estimate is to have an expert HVAC contractor inspect your home.


Choosing the proper size AC unit for your home or office is a complex decision. When you choose a big size AC unit more than the required size to cool the area. It will not only cool the area rapidly but will reduce the efficiency which will result in higher energy bills. We have also seen the calculation of the AC unit size compared to the area that needs to be cooled. Lastly, to get the best expert advice contact us at 650-223-2028 or get an appointment.